1. Field of the Invention
This invention relates to fluoropolymer compositions that do not contain substantial quantities of problematic perfluorooctanylsulfonate compounds, that have desirable environmental properties, such as noncombustibility, decreased volatility, do not deplete ozone, and that are suitable as oil and/or water repellency treatments for fiber, fabrics, and carpets. The invention also relates to methods for producing such compounds that result in compositions that do not require removal of the polymerization solvent prior to application or use of the compositions.
2. Description of Related Art
Fluorine containing compounds have been in development and use for 50 years. Fluorine is used to create pharmaceutical drugs used to treat diseases in humans and animals. Fluorine is also used to create polymers that excellent barrier properties, suitable for use in medical devices, such as the heart lung machine, the kidney dialysis machine, and the fluid bags that store and deliver life-giving fluids during medical treatments and surgical operations. Fluorinated polymers are used to produce bandages for open skin wounds and burns, filters for air purification, military clothing, outdoor apparel, resins for use in paints and gel-coatings used on boats, and food packaging. The carbon-fluorine bond is one of the strongest single bonds known to the chemist, and as a result, fluorinated carbon polymers are particularly suitable for use in situations where thermal stability to very high temperatures is required of polymeric materials. Polymer products such as Dupont Teflon are known for their ability to withstand the heating and thermal fluctuation conditions that are encountered in outer space. Teflon is well known for its performance in cookware, in seals and gaskets, and as a wire coating.
In recent times, the use of sulfur-containing fluoropolymers having a perfluorocarbon chain length of eight carbons (typically known as perfluorooctylsulfonates, or PFOS) have been criticized for their bioaccumulative effects. These compounds and compositions containing them have been and will likely continue to be, the subject of intense regulatory scrutiny, and generally negative recommendations relating to their continued manufacture and use. Similarly, the decomposition effects of C-8 perfluorocarbon compounds having alcohol (OH) reactive groups that are esterified rather than sulfonated are being carefully evaluated by regulatory and industry groups, because these compounds have the potential to decompose into the corresponding C-8 perfluoro-alcohol under certain conditions. As with PFOS, the bioaccumulative effects of these alcohols is of concern to regulatory agencies.
Both sulfonated perfluoro compounds and perfluoro alcohols having 8 perfluorocarbon atoms appear to have reactive groups that can decompose to substances that accumulate in biological filter systems, such as stream beds or filtering organs of mammals.
Telomerization is a radical displacement or chain transfer reaction that results in the production of large numbers of small sized monomer molecules. However, telomerization results in a distribution of materials of different chain lengths. Perfluorinated telomers can be prepared using building blocks of, e.g., C2:F4, (i.e., of fluorinated ethylene). Examples of telomeric processes for producing perfluorocarbon compounds include processes for linking together tetrafluoroethylene into controlled carbon size oligomers, including those processes practiced by Dupont, Clariant, Asahi Glass, and Daikin. Examples of perfluorinated alcohols include ZONYL (Dupont) and FLUOWET (Clariant).
Perfluorinated compounds can also be produced by direct fluorination of existing carbon chains, e.g., by fluorination with HF or F2. Examples of such processes are described in U.S. Pat. Nos. 5,506,309; 5,523,496; 5,539,059; 5,543,567; 5,557,012; 5,571,870; 5,674,949; and 5,753,776.
Neither the telomerization literature nor the direct fluorination literature discloses compositions containing oil and/or water repellent agents containing a perfluorinated carbon moiety, an unfluorinated carbon linkage, and a reactive group, such as a (meth)acryloyloxy group, that can be polymerized or copolymerized into an effective oil or water repellent, that is free of PFOS, that can be polymerized in a non-VOC, noncombustible, non-ozone depleting solvent, and that can be formulated into a repellent composition without separation from this solvent, and applied directly onto the treatment substrate.
Because of the very real prospect that the production of PFOS and its analogs will continue to be viewed with strict regulatory scrutiny, there exists a need in the art for compositions and methods of producing compositions that are suitable for use in oil and/or water repellency applications, but that do not involve the production of PFOS or its analogs in appreciable quantities.